1. Field of the Invention
The present invention relates to a bus driver and a driver each of which has a temperature detecting system. The present invention also relates to an output adjusting method for controlling operations of a circuit in accordance with a temperature of the circuit.
2. Description of the Related Art
A plurality of units (Central Processing Unit, Memory Unit or the like) included in a single system are connected with each other via a bus comprising a plurality of transmission paths. Signals (data and the like) are transmitted between the plurality of units via the bus.
Each of the units connected to the bus includes an output buffer for driving the bus (i.e. for outputting signals to the bus) and an input buffer for receiving signals transmitted on the bus.
Since the signal is transmitted via the output buffer, a voltage level of an output signal becomes stable, and the output signal can be stabilizingly output to the bus.
To maximize driving performance of the bus, as shown in FIG. 6, an output buffer may be used, wherein an "n" ("n" is an integer equal to or greater than "2") number of buffer circuits 501 are connected in parallel. This type of output buffer can accurately drive the bus at high speed compared to the case where a single buffer circuit is used, because the driving performance (performance for current-supply) of the bus can be enhanced by "n" times.
However, as a temperature of the output buffer including the plurality of parallelly-connected buffer circuits 501 rises, signals are output from the buffer circuits 501 respectively at different phases. Therefore, a ringing event occurs in a signal which is generated as a combination of the signals from the buffer circuits 501.
If the ringing event occurs in the signal generated as the combination of the output signals from the output buffer, a problem may arise that the unit receiving the generated signal is operated inappropriately.
A similar problem commonly appears not only in the output buffer circuit, but in an electric circuit comprising a plurality of parallelly-operating circuits.